A recent development in the field of wireless telecommunications is the capability of transmitting data through packet-switched networks. Perhaps the most well-known packet-switched network is the “Internet” world-wide computer network, which is also often referred to as the “World-Wide Web.” Another familiar packet-switched network is a “Local Area Network” or “LAN” which is used principally to interconnect personal and other computers within an office or other enterprise.
Packet-switched networks are typically characterized by the transmission of data in a string of separate “packets” or “frames,” each of which may be directed through different paths through the packet-switched network to the same ultimate destination. Upon receipt at the destination, the packets of information are assembled and used in the correct, original order, as if the entire string had arrived in that order, following the same physical path.
Due to the flexibility, capabilities and speed associated, network systems, standards and transmission protocols are being developed to transmit data and voice to a single wireless terminal. Such terminals include mobile telephones, personal computers (such as laptops) and the like through which a user may desire to send both voice and data communications. Perhaps the most common example of such activities is use of a mobile phone to make telephone calls and also to send and receive e-mail messages and access web pages on the Internet. Use of wireless terminals for this dual purpose is expected to increase as telephone, fax and data transmission services continue to converge. Eventually, it is expected that mobile telephones and personal computers will utilize wireless technology to allow both mobile telephone calls and access to packet-switched networks without the need for land line connections. Other applications will be apparent, as well, to one of ordinary skill in the art and may be developed in the future.
Existing wireless systems providing voice and SMS services utilize “circuit-switched” networks to direct their transmissions. As currently envisioned, wireless data transmission services will be delivered through a “packet-switched” network that is physically separate from wireless networks presently providing circuit voice, limited circuit data and limited Short Message Service (SMS) services. Circuit-switched systems differ fundamentally from packet-switched systems in that all information comprising the call or SMS follows the same fixed-sized path within the network and, therefore, cannot provide the same capacity and performance for transmission of data at acceptable costs. Consequently, physically separate packet-switched networks will be constructed to provide wireless data transmissions services, in addition to the existing and developing circuit-switched systems offering voice and SMS transmission services. A network protocol used by packet-switched and circuit-switched networks to communicate with each other is ANSI-41.
As envisioned, a mobile terminal will communicate with the packet-switched network in the transmission of data. When a telephone call, for example, is made requiring transmission of voice information, the mobile terminal will communicate with the circuit-switched network. Examples of circuit-switched networks in existence and under development are AMPS, TDMA, GMS, CDMA, and CDMA 2000. Examples of a number of available packet-switched networks providing wireless data transmission services include GPRS (General Packet Radio Service) data networks, also identified as GPRS-136, and EDGE (Enhanced Datarate Global Evolution) also identified as GPRS-136HS.
However, certain inefficiencies are inherent in using both circuit-switched and packet-switched systems to provide wireless voice and data transmission services. In particular, as currently envisioned, a mobile terminal relying on both networks for voice and data services will “camp on” or remain in communication this approach tends to preserve resources of both systems by reducing the amount of air time and control messaging that would otherwise be required if the mobile terminal camped on the system transmitting telephone calls and SMS messages, doing so creates a delay (typically 3 to 5 seconds per call) in connecting or completing setup of incoming calls to the mobile terminal.
Because the mobile terminal will be camped on the network providing data transmission services at the time of an incoming telephone call or SMS message, the page message typically used to alert the mobile terminal to the call and request a response is directed through the data transmission network. This is considered preferable because information representing the location of the mobile terminal is also highly likely to be known by the data network on which the mobile terminal is camped. Such location information is used to route the page request to the packet-switch currently servicing the mobile terminal. Although forwarding the page request through the data network avoids unnecessary use of transmission resources of the circuit-switched voice network that would otherwise be required to transmit a global page to all locations within the network or direct a page to an area in which the mobile terminal is not found, additional delay in both sending the page and receiving a response from the mobile terminal is occasioned. It will be apparent that such delay undesirably consumes additional resources of the voice network while awaiting a response from the mobile terminal and reduces the grade of service to the calling party and the mobile terminal user as they await setup of the call.